Dorsey & Whitney's Marianne Short, head of one of the top 100 U.S. law firms, is moving to UnitedHealth Group Inc., the nation's largest health insurer, to become its chief legal counsel, the Minnetonka-based company announced Tuesday.

For Short, 61, it is her first assignment on the client side of the corporate legal equation and rounds out a career that includes stints as an assistant attorney general, judge, trial attorney and managing partner of a 565-member law firm with revenue exceeding $300 million a year.

For UnitedHealth, Short is the latest in a series of Dorsey attorneys to fill the ranks of its legal team. Dorsey has been the company's top outside counsel almost since its inception in the mid-1970s.

"Marianne is a highly experienced and wise counselor with deep legal skills, exceptional business judgment and significant experience in health care," said UnitedHealth Group CEO Stephen Hemsley.

Short replaces Richard Baer, 55, who is returning to his home in Denver to serve as general counsel for Liberty Media Corp.

Short, arguably one of the most influential women in Minnesota's legal landscape, said it was "difficult" to leave the only law firm she's known as a professional.

But, she added, "I'm excited about joining UnitedHealth Group's leadership team and the opportunity to be a part of this highly successful and diversified health care services provider."

Herbert Kritzer, a professor at the University of Minnesota Law School who teaches about the business of law, said it is not uncommon for senior attorneys to become in-house counsel for a private-sector client.

"Maybe she was tired of management work. Five years is a long stretch," Kritzer said. "And it's an interesting time to move into the health care world with all the reform going on."

Short, whose move to UnitedHealth surprised most in her firm, has been Dorsey's managing partner since 2007. She originally joined the firm in 1977 after a stint as a special assistant attorney general for the state of Minnesota. From 1988 to 2000, she served as a judge on the Minnesota Court of Appeals.

Dorsey's policy committee will select a successor.

Short's former colleagues spoke warmly of her tenure with the firm. Former Vice President Walter Mondale, a Dorsey partner, said "Marianne Short has been a magnificent and respected leader of the Dorsey law firm, which is one of our nation's most successful legal partnerships."

Difficult times at Dorsey

But Short also presided over some difficult times for Dorsey and the legal industry, even as the firm celebrated its centennial anniversary earlier this year.

In a period marked by more years of recession than not, Dorsey's revenue went from $373 million in 2007 to $323.7 million in 2011, the last year for which revenue was available. The number of lawyers during the period declined from 680 to 565.

Short recently acknowledged that the firm also is shopping for a new, smaller space for its Minneapolis office because of its more modest needs.

"This has not been a great time for the legal services profession in general and large firms specifically," said Kritzer.

On top of the tough economics of the legal profession, Dorsey also suffered a blow to its pride earlier this year when the Minneapolis law firm of Faegre & Benson merged with the Indianapolis firm of Baker Daniels to create Faegre Baker Daniels and take honors as the largest Minnesota-based firm.

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